Sam Taylor-Johnson's film of the EL James S&M bestseller isn't nearly as painful as it could have been

Except for the new instalment of Star Wars, there is no more steamily anticipatedfilm this year than Fifty Shades of Grey. Advance ticket sales, boosted by its Valentine’s Day release, have been record-breaking.

In book form, the “erotic trilogy” of British authorEL Jameshas sold over 100m copies worldwide. And the producers’ casting hunt for actors to play starry-eyed ingénue Anastasia Steele and her bondage-obsessed new paramour, the endlessly mysterious billionaire Christian Grey, has been a magnet for more tabloid speculation than typically greets a royal birth.

Not bad for a book that started out as Twilight fan-fiction, and whose prose style might charitably be described as unspeakable. The challenge for Sam Taylor-Johnson, the Turner Prize-nominated fine art photographer who directed 2009’s John Lennon biopic Nowhere Boy, was to please the books’ legion of (predominantly female) fans without allowing the film to become a soft-pornographic laughing stock.

Cinema, one would hope, has certain advantages over literary inner monologue such as this: “My heartbeat has picked up, and my medulla oblongata has neglected to fire any synapses to make me breathe,” which Ana declares in one of the early chapters, as Christian announces he’s having a shower. If she described her digestive processes in such prissily scientific detail, we’d be here all day.

Dakota Johnson, daughter of actors Don Johnson and Melanie Griffith, has screenwriter Kelly Marcel to thank that the film adaptation eliminates this bubblehead stream of consciousness, allowing the camera instead to occupy Ana’s point of view. It’s usually a view of Jamie Dornan, the Northern Irish actor best-known for playing a hot serial killer in BBC Two’s The Fall, who was a late replacement after the original choice, Charlie Hunnam, got cold feet.

The lack of a customary press conference in Berlin, where the film held its world premiere, has fuelled speculation that the two stars can barely stand each other’s company. Neither has been at pains to dispel these rumours, and Taylor-Johnson has openly talked about her on-set battle with James to defend every decision even minutely diverging from the book.

The film's biggest single asset is Dakota Johnson: gone is the book's blithering simpleton

So how has it all worked out? Almost shockingly well, considering. It proves that age-old saw that great books rarely make great films, whereas barely-literate junk can turn into something ripe and even electric on screen. The lead performances and sleek style choices sell it almost irresistibly to the target audience, but the film has the confidence to end bruisingly unresolved, with the structural equivalent of a slap in the face.

Meanwhile, for anyone who struggled to wade through the gruelling mire of James's verbiage, it's almost a form of revenge to watch the filmmaking slice through it, cleanly stripping off the fat. Great art it's not – but it's frisky, in charge of itself, and about as keenly felt a vision of this S&M power game we could realistically have expected to see.

The film’s single biggest asset is Johnson, who has worked hard with Marcel and Taylor-Johnson to perform a three-woman salvage job on the character of Anastasia. Gone is the book’s blithering simpleton, with her arsenal of “holy hell”s and “double crap"s and “oh my"s. Her inner goddess is, thank goodness, nowhere to be found or heard. She is at no point a quivering, moist mess, and doesn’t make the ruinous error of thinking the word “f___” is an epithet.

Instead, she projects an instantly compelling blend of vulnerability and spiky resistance – qualities that sometimes remind you of Griffith in her early roles. There’s more fight in this Ana than you’re ever expecting, and it raises the stakes during each stage of her seduction by Christian, from the moment she meets his eyes during an interview for her college paper.

Grey, for obvious reasons, is much more vividly described in the book than she is. Dornan, with his tousled hair and chunky build, is a precise physical match for this ludicrous fantasy-hottie-Bluebeard role, and somehow manages to render it only intermittently absurd. A good kind of absurd.

On purpose, he’s a little inexpressive at first: cold slate, with questioning eyes. The film doesn’t ever get totally under his skin and doesn’t want to – it needs to recoil, with a shiver of uncertainty, as we get to grips with his predilections.

The sex scenes clamber up the scale in intensity, without ever really threatening to get white-hot, and feature a lot more of Johnson than they do of Dornan. You could say she’s submissive to the point of baring all, from most angles, whereas he’s dominant enough to keep the camera from straying down where he doesn’t want it. Even when Grey, with his riding crops and cat-o’-nine-tails and Red Room of Pain, would claim otherwise, these sequences stay well within the bounds of vanilla mainstream taste.

And they offer an easy answer to the following question. Would you rather read an assortment of appallingly organised words describing two stick-thin characters yelping on the page, or watch two very attractive young stars going at it, in images filmed by Seamus McGarvey? This great cinematographer – he also shot The Hours, We Need to Talk About Kevin and Godzilla – is a ready-made cornerstone for the flatly indisputable argument that Fifty Shades is a far better film than it was a book.

Anastasia is no walkover here and sometimes gives as good as she gets, if not better. The funniest scene – debatably the sexiest, too – has the duo sitting at either end of a glass boardroom table, while Ana whips through the contract for their experimental relationship scratching out everything she won’t consent to. The script isn’t afraid to call a spade a spade here: “Find anal fisting. Strike it out.”

Johnson’s timing and verve are terrific, and manage to upend the more distasteful indignities of the book in gold-spun-from-straw ways. It’s her rebellion, not just her submission, that this version of Christian finds attractive, which gives Dornan something more interesting, human, and contradictory to play as well. If Taylor-Johnson and James bitterly tussled for control over this material, it's a relief and even a bit of a thrill that the director came out on top.